Abstract:The formation mechanism of P-Δ effect of bridge double-pile foundation in steep slope was analyzed. According to the theory of the earth pressure and the elastic foundation beam, a pile-soil interaction model was established on the basis of the reasonably simplified residual pushing force and soil resistance, and then the differential equation of the characteristic section of piles was deduced with consideration of the P-Δ effect, and the solution to the calculation of the inner-force of the double-pile was obtained by using the power-progression method. In addition, a comparative analysis of an existing literature was carried out, and it has been found that the calculated values are closed to the measured values. Finally, the influencing factors and sensitivity of inner force and the displacement of the bridge double-pile were studied and some useful conclusions have been drawn: the P-Δ effect of the former-pile can not be ignored; the moment of the back-pile is bigger than the former-pile when the load level and the soil resistance coefficient m are the same, and the maximum bending moment surfaces of the pile is near the sliding surface. The effect of embedded depth also exists in the piles in steep slope.

Abstract:The crack width on structural concrete surface is one of the most important parameters in the detection and assessment of concrete structures. At present，the contact-based method is commonly used by inspectors to detect the maximum width of crack. However, this method is a great consumption of time and energy and can not measure the maximum width of crack accurately. Based on the application of image analysis technology, a new non-contact method was proposed in this paper, which used the calibration block on the concrete surface and revised the original deformed images, thus enhancing the contrast of the revised image and smoothing them, etc. Finally, the width of crack in the image can be calculated. The method has been verified by the laboratory experiment of a cracked concrete girder using vertical and oblique photographic techniques to detect the cracks and the accuracy of 93.4% and 90.9% have been obtained, which have shown that this new method can effectively detect the width of crack.

Abstract:Based on the existing statistical results of concrete and steel bar’s mechanical properties at high temperature, the probabilistic models for concrete and steel bar’s relative strengths at high temperature were extended to a larger thermal range. Considering the randomicity of concrete and steel bar’s strengths in the sectional analysis of axially loaded columns in fire, the statistical characteristics of the columns’ sectional load bearing capacities were studied. The results have shown that: (a) whether the randomicity of concrete and steel bar’s strengths at room temperature are considered or not, the columns’ sectional load bearing capacities in fire follow the normal distribution; (b) the randomicity of concrete and steel bar’s strengths at room temperature has almost no influence on the mean values of the columns’ sectional load bearing capacities in fire, but has significant effect on their variation factors; and (c) the mean values of the columns’ sectional load bearing capacities in fire can be directly determined through calculation by using both the mean values of concrete and steel bar’s strengths at room temperature and the mean values of their relative strengths at high temperature.

Abstract:Referring to the investigation data of rural residence in Hunan Province, the indexes were analyzed and their weight value was determined and ranked. Second-calculation fuzzy evaluation method was used to appraise the residence-safety level of the survey area. The results have shown that the analytic hierarchy process and fuzzy evaluation method can not only appraise the residence-safety level objectively, but also give some suggestions according to the weight value of the indexes.

Abstract:The simulation and analysis of the Changsha urban thermal environment and the analysis of the infrared temperature map of Changsha urban area were presented. The results have shown that green land and water coverage have significant effects on alleviating the urban heat island effect and improving urban air quality. The results have also shown that the road layout of the city is really relevant to urban regional thermal environment, and the rational design of urban road layout may take the advantage of the prevailing wind for natural ventilation, and the layout of high-rise buildings should be coincident with the urban road direction to utilize the urban roads ventilation to improve the thermal environment.

Abstract:The effect of reactive temperature and space velocity on the storage-release characteristics of NH3 was investigated on the dynamic reaction model of SCR catalytic reaction. The result has shown that the storage amount of NH3 increases with the increase of reactive temperature, the impact of reactive space velocity on NH3 storage amount shows different characteristics in different temperature ranges, the decreasing trend of NH3 storage amount increases with the increase of reactive space velocity when the temperature is between 200 ℃ and 300 ℃, and the decreasing trend of NH3 storage amount decreases with the increase of reactive space velocity when the temperature is over 300 ℃. Reactive temperature and space velocity also have effect on the storage and release velocity of NH3.

Abstract:The displacements and stresses for various thickness-to-span ratios were obtained using the boundary element method (BEM) for Reissner’s moderately thick plates, and the finite element method (FEM) for Mindlin’s moderately thick plates and three dimensional problems.The applicable range and accuracy among the three dimensional theories, the moderately thick plate theory and thin plate theory were defined. A theory basis and reference for choosing the thin plate theory, the thick plate theory or the three dimensional theory to analyze plates were provided. The results have shown that shear locking is deleted when the reduced integration is used in the finite element of plates and shells.

Abstract:Aiming at geometrically nonlinear problems and using movement transformation as a point of departure, a global weak form integral equation was established from the virtual power principle on the basis of the S-R decomposition theorem and updated co-moving coordinate formulation. Numerical solutions were obtained by using element free Galerkin method (EFG). Usually, incremental and iterative methods are used to solve the nonlinear problems of numerical calculation. S-R decomposition theorem brings out a new strain tensor, which can reasonably reflect the state of stain and rotation on the condition of large displacement and large rotation, and are helpful in solving geometrically nonlinear problems. Numerical examples have shown that this method is reasonable and effective.

Abstract:To increase the precision of high pressure common rail forecast model, the modeling of high pressure common rail diesel engine based on AMESim was introduced. On this basis, grey relational theoretical analysis was used to analyze the multi-parameter system and calculation to determine the input and output variables of the predictive model. Adaptive weighted Particle Swarm Optimization algorithm was applied to the optimization of initial parameters of least square support vector machine. Through the examination of 20 forecasting samples, the maximal error of the forecast model is 0.079 1, and the average relative error is reduced to 0.039 6 by the least square support vector machine, which is far superior to commonly used empirical formula and neural network.

Abstract:Based on the analysis of the mathematical model of permanent magnet synchronous motor (PMSM), a new direct torque control system based on space vector pulse width modulation technique (SVM-DTC) is proposed. The stator flux and torque were regulated by PI controllers to decouple motor space vector in the two components of stator flux and torque. Meanwhile, a stator flux estimation method based on rotor position and stator current was used and sensorless was designed to estimate the rotor position. Simulation and experiment results have shown that the proposed method can effectively estimate the stator flux and reduce the electromagnetic torque and stator flux ripple, so the system has good static and dynamic performances.

Abstract:To address the speed limit of Interior Permanent Magnet Synchronous Motors（IPMSM） due to DC bus voltage, a simplified flux-weakening control method based on voltage coordinate system was presented. The analysis of vector control based on current coordinate system is converted into voltage coordinate system, and the expression of torque based on voltage coordinate is derived. With weakening control strategy, the current components are controlled according to the limit voltage. Theoretical analysis and simulation results have shown that this method has such advantages as simple calculation, maximum efficiency of DC voltage, wider range of speed and good dynamic response.

Abstract:The catalytic graphitization of carbon fibers with electrodeposited Fe-P alloy coating and the relationship between coating composition and graphitization temperature were studied. Carbon fibers with and without electrodeposited Fe-P coating were heat treated at different temperatures and the structural changes were characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscope. The results have indicated that Fe-P alloy exhibits a significant catalytic effect on the graphitization of carbon fibers. The degree of graphitization of polyacrylonitrile (PAN)-based carbon fibers coated with Fe-P alloy (7% P) reaches 71% through heat treatment at 1 000 ℃. However, the degree of graphitization of carbon fibers without Fe-P alloy is only 30.1% after being heat treated at 2 800 ℃. The presence of Fe-P alloy catalyst greatly decreases the graphitization temperature of carbon fibers. Moreover, the degree of graphitization of the Fe-P alloy coated carbon fibers increases with the increase of P content in the Fe-P alloy. The degree of graphitization increases with the increase of the deposition time of Fe-P alloy, and remains unchanged until the thickness of the Fe-P alloy coating reaches a certain value. The mechanism of catalytic graphitization was also discussed and the results have shown that the effect of Fe-P alloy on carbon fibre catalytic graphitization follows the dissolve- precipitation mechanism.

Abstract:Ten quinolone-bonded porphyrins were designed and synthesized on the basis of both porphyrin’s photosensitivity and special affinity for tumor cells and quinolones’ antitumor and anticancer activities. The molecular structures of all synthesized compounds were characterized with 1H NMR, IR, UV-Vis and MS. The interaction between quinolone-bonded porphyrins and bovine serum albumin (BSA) was investigated with fluorescence spectrum. The results have shown that these new quinolone-bonded porphyrins have a powerful ability of quenching the fluorescence of BSA via static quenching.

Abstract:Using typical chlorobenzenes 1,2,3-trichlorobenzene (1,2,3-TCB) as the target removal, experiments were done for the adsorption and photocatalytic degradation synergistic reaction of Multi-walled Carbon Nanotubes of TiO2 (MWNTs/TiO2). The results showed a calculated curve that superimposed in the removal rate of 1,2,3-TCB adsorbed on MWNTs and the degradation rate of the nano-TiO2 for 1,2,3-TCB was always below the curve of 1,2,3-TCB removal rate through the adsorption and photocatalytic degradation synergistic reaction of MWNTs/TiO2 in conditions of different solution temperatures, pH, dosages of MWNTs/TiO2, and the intensity of UV light, which has fully reflected that MWNTs/TiO2 has adsorption and photodegradation synergistic reaction. The solution temperature or pH values decrease will help MWNTs/TiO2 to remove 1,2,3-TCB, increase the dosage of MWNTs/TiO2, or the intensity of UV light will help MWNTs/TiO2 to remove 1,2,3 - TCB.

Abstract:A predictive method of microbial clogging assessment was presented on the basis of the microorganism growth theory and the quality relationship between the amount of biofilm and hydraulic conductivity of porous media. Furthermore, we applied this method to evaluate potential microbial clogging degree of the recharge water in Pinggu. The results have shown that clogging occurs within the upper 0.5 m near the land surface with a permeability reduction of only 2.3%.

Abstract:Considering the layout characteristics of general industrial enterprise freight transport railway lines (both layout with radial and tree branch), an intelligent optimization method is presented. This method is built on the basis of the placing-in and taking-out operation model, and then, the problem is decomposed into several small scale sub-problems. Furthermore, a two-level optimization strategy is proposed by parallel solving the optimization sub-problems inside the shops with tree branch lines, then solving the optimization problems between the shops in radial line. According to the optimization strategy, a hybrid genetic elite ant colony algorithm is designed for the placing-in and taking-out operation optimization problem. Simulation results prove that the proposed method can effectively optimize the railway placing-in and taking-out operation problem.

Abstract:In this paper, we propose a non-embedded watermarking based on a trusted third party, coefficients features of DCT and edge detection. The algorithm first calculates the edge information of the images by DCT coefficients and then computes authentication codes with the edge information. The non-embedded watermarking technology avoids the damage of the original image, which is caused by traditional watermarking. The experiments have shown that, compared with conventional DCT-based watermarking algorithm，the algorithm proposed in this paper is much more efficient in resisting general image processing operations (e.g. sharpening, noising, invert, etc), JPEG compression, and geometric attacks (e.g. rotation, cropping, etc).